EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF AERODYNAMIC INTERACTION DURING SABOT SEPARATION

As part of a TTCP cooperative research program between ARL (US), DRA (UK) and DREV on the aerodynamics of sabot separation (KTA 2-11), a series of supersonic wind tunnel tests were performed in the DREV 0.6 m x 0.6 m indraft facility in order to obtain experimental data on surface static pressure distribution and aerodynamic coefficients. Two model variants were used: a full scale model of the C-76 Armour-Piercing Fin-Stabilized Discarding-Sabot (APFSDS) projectile and a generic APFSDS model. The relative attitudes and locations of the sabot/projectile system were frozen in test section, providing twelve configurations of each variant. The results were obtained at Mach 3.5 and 4. They indicated that the generic variant gave results very similar to those of the C-76 variant. In addition to wind tunnel experiments, Computational Fluid Dynamics (CFD) calculations were performed on the generic configurations using a 3D Navier-Stokes code (TASCflow). The predicted results showed good agreement with the wind tunnel results. An analysis of the expected trajectory deviation due to the aerodynamic interference of sabot separation was performed. It indicated that the magnitude of the aerodynamic interference measured int he wind tunnel would generate a trajectory deviation similar to that observed in firing trials.